This invention relates to a locking device for attachment to the male electric plug on the power supply line to an electric appliance for the purpose of preventing use of the appliance until the device has been removed.
Locking devices for this purpose have been available in the prior art for many years, and typical examples of the prior art approaches are found in the U.S. Pats. No. 2,654,073 of 1953 to Katz, McEneaney U.S. Pat. No. 2,664,734 of 1954, Evalt U.S. Pat. No. 2,733,716 of 1956, Sherman U.S. Pat. No. 4,167,658 of 1979 and Wiencke U.S. Pat. No. 4,445,738 of 1979 and Wiencke U.S. Pat. No. 4,445,738 of 1984. The characteristic common to the devices of all of these patents is their relative complexity, particularly including the number and variety of the parts which each of the complete devices is composed.